1. Field of the Invention
The present invention relates generally to methods of treating sugar juices, syrups, and related products, offering compositions of matter and processes incorporating the same.
2. Description of the Prior Art
In the sugar milling process, a sucrose-bearing juice is obtained by extracting the juices from a suitable plant source such as sugar cane. The impure juice is clarified in the sugar mill, typically with a sulfitation process. In the sulfitation process, sulfur is burned in air, to form sulfur dioxide gas. The impure sugar juice is passed through sulfitation towers wherein the sulfur dioxide gas is typically passed counter-currently to the juice. The sulfitation towers can contain perforated trays to enhance the contact of sulfur dioxide gas with the juice. Lime is added to the juice, to neutralize the natural acidity of the juice, as well as the acidity introduced by the sulfur dioxide. The lime also serves to form multiple insoluble calcium precipitates. A polymer flocculant, such as a polyacrylamide, is normally added to the juice just prior to the clarifier, to assist in the settling rate of impurities. The juice is heated to approximately 105 Celsius, and introduced to clarifier tanks where the juice is maintained at 90-105 Celsius for approximately 45 minutes to 2 hours, while various impurities settle to the bottom of the juice clarifier. The clarified juice taken from the top of the clarifier is then evaporated to raw syrup. The raw syrup may optionally undergo a syrup flotation-type clarification where the impurities are removed from the top of the clarifier. If utilized, the syrup clarification typically uses phosphoric acid, lime, and polymer flocculant; aeration enables the impurities to float to the top of the clarifier where they are removed as scums. The sugar syrup (whether clarified in a syrup clarifier or not) is crystallized to form crystals sugars for consumption, or for further refining in a sugar refinery.
More recent processes for sugar juices and syrup clarification include those exemplified by U.S. Pat. No. 5,281,279 to Gil et al. This patent describes a process for producing refined sugar from raw sugar juices. The process includes adding a flocculant for treating raw sugar juice, wherein the flocculant is selected from the group of lime, a source of phosphate ions, polyelectrolyte, and combinations thereof. The thus treated juice is concentrated by evaporation to form a syrup, with a subsequent treatment by flocculant, then filtered, and then decolorized and de-ashed using ion-exchange resin.
In U.S. Pat. No. 4,247,340, Cartier claims a process for purifying impure sugar solutions, including simultaneous decolorization and clarification, comprising contacting the impure sugar solutions with submicroscopic ion-exchange resin in the forms of approximately spherical beads, said ion-exchange resin having diameters from about 0.01 to 1.5 microns, followed by separation of this ion-exchange resin from the sugar solution. The ion-exchange resin particles may be separated in the form of a floc, wherein the floc may be formed either from impurities in the impure sugar solution, or by adding sufficient flocculating agent in the sugar solution to flocculate all of the resin particles.
Another example of more recently proposed sugar clarification includes that of U.S. Pat. No. 5,262,328 to Clarke et al, detailing a composition for the clarification of sugar bearing juices and related products. The composition comprises a dry, powdered admixture of aluminum chloride hydroxide, lime, and activated bentonite. The composition may also include a polymer flocculating agent, such as a polyacrylamide.